For example, a plug connector of a multi-poled zero insertion force (ZIF) connector type has an insulator to which a plurality of contactors is fixed, and a substrate housed inside the insulator. The substrate has an electrode pad electrically connected to the contactor. A lead contact part of the contactor and the electrode pad of the substrate are soldered to each other, whereby electrical connection is fixed. By fixing the lead contact part of the contactor and the electrode pad of the substrate by soldering, sufficient connection strength between the lead contact part of the contactor and the electrode pad of the substrate can be obtained.
Soldering work between the lead contact part of the contactor and the electrode pad of the substrate is generally performed by hand using soldering iron (for example, see Patent Documents 1, 2).